This invention relates to processes for the preparation of cyanoalkylphenols.
Cyanoalkylphenols have numerous applications and are particularly useful as chemical intermediates in the preparation of polyurethanes, epoxy resins and pharmaceutical and agricultural products.
Methods are known for preparing cyanoalkylphenols. One process for the preparation of cyanoalkylphenols involves a complex multi-step synthesis whereby a dimethylbenzylhalide is converted to the cyanide, ring nitrated, hydrogenated, and then subjected to diazotization. See A. Johnsson, Act. Chem. Scand 8, 1203-10 (1954). The problem with this process is that it is a low-yielding, multi-step, time-consuming, and uneconomical route.
Another process for the preparation of cyanoalkylphenols is disclosed in U.S. Pat. No. 4,405,528. This is a process for the synthesis of 4-(.alpha.-alkyl-.alpha.-cyanomethyl)-2,6-disubstituted phenol by reacting a 2,6-disubstituted phenol with a Friedel-Crafts addition agent in the presence of a Friedel-Crafts catalyst such as aluminum chloride to form the corresponding 4-(.alpha.-alkyl-.alpha.-oxomethyl)-2,6-disubstituted phenol, reducing the 4-(.alpha.-alkyl-.alpha.-oxomethyl)-2,6-disubstituted phenol to form the corresponding 4-(.alpha.-alkyl-.alpha.-hydroxymethyl)-2,6-disubstituted phenol and thereafter reacting the 4-(.alpha.-alkyl-.alpha.-hydroxymethyl)-2,6-disubstituted phenol with an alkali metal cyanide or an alkaline earth metal cyanide to form the desired 4-(.alpha.-alkyl-.alpha.-cyanomethyl)-2,6-disubstituted phenol.
A process for the preparation of 4-(.alpha.-hydrocarbyl-.alpha.-cyanomethyl)-2,6-disubstituted phenols is disclosed in U.S. Pat. No. 4,483,800 wherein said cyanomethylphenol is prepared by reacting a disubstituted phenol with an aldehyde and an alkali metal cyanide or an alkaline earth metal cyanide in a suitable solvent.
What is needed is a versatile one-step process for utilizing inexpensive, readily available starting materials to produce cyanoalkylphenols.